Radiological technologists [6]
 Aberration frequencies (Cu- and Cs-cells)

(Moving window averaging with step of 5 workers)
(Workers with D2>20 rad were excluded)

Dose uncertainty is large before the personal dose monitor systems are introduced (i.e., 1956-1960).
The accumulated dose of about 60 cGy corresponds to the time of the introduction of dose monitoring system.

The chromosome aberration frequencies in persons after the introduction of dosimeters are shown in the figures presented below.The increment of aberrations is apparent only in the Cu cells. But, that of Cs cells is absent or very small if any.










Sasaki, M. S. (2003):
Radioadaptive response and genomic instability: a phenotypic dichotomy of gene-environment interaction. In, Shibata, Y., Yamashita, S., Watanabe, M. and Tomonaga, M. eds. “Radiation and Humankind”. Elsevier International Congress Series 1258, pp.11-19.











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Dose response kinetics (below 60 cGy) (persons who were not wearing dosimeters were excluded)
(1) Cu cells
  U=C0+akd/λ[1-exp(-X/d/λ)]
  C0 is age dependent increase of Cu cells in unexposed persons,
            C0=0.001+3.80×10-5×age (year)
          X is accumulated dose (cGy)
          λ is mean lymphocyte lifetime, 1000 days
          d is yearly dose, d=0.313+0.0236∙X
          a is the induction rate, ka=8.003×10-4/cGy

(2) Cs cells
   S=C0+aX
         C0=1.16×10-5+2.59×10-5×age (year)
          a is the induction rate on a per cGy basis.
           For the low dose-rate exposure, estimation of the induction rate (a) is practically difficult probably because the low dose photons (probably neutrons too) erase the birth of spontaneous translocations in the hematopoietic system.

Age-dependency of spontaneous aberration frequencies are taken from Tonomura et al. (1983).
Tonomura, A., Kishi, K. and Saito, F. (1983). Types and frequencies of chromosome aberrations in peripheral lymphocytes of general populations. In, Ishihara, T. and Sasaki, M. S. eds. “Radiation-induced Chromosome Damage in Man”. Alan R. Liss, Inc., New York. pp.605-616.